Friday, 27 April 2012

10 years since the last conversation with Pioneer 10

Today, April 27th 2012, the Space Shuttle Enterprise will arrive in New York. There'll be lots of media coverage for something so photogenic, and thousands of pictures and amateur videos of the flight will be posted on social media and online newspapers.

That's all good, but arguably the anniversary of something even more astounding in space exploration also happens today. And it probably won't get much of a mention in any of the news media.

There have been many spacecraft launched out of the earth's atmosphere. Orbiters, rockets to the moon, rockets to other planets, to asteroids, or even comets.

But few have gone on to leave the planets of the solar system and travel onwards towards ... well, the stars, basically. Just four so far; Pioneer 10 and 11, and Voyager 1 and 2, with New Horizons due to join them as the fifth escapee in a few years, once it's finished having a good look at Pluto.

Pioneer 10 was the first. Today marks the 10th anniversary of the last intelligible "conversation" between machines here on Earth, and Pioneer 10, when it transmitted 33 minutes of telemetry (clean data) from 80.22 astronomical units away.

Or, to put it another way, a spacecraft made with 60s and early 70s technology, that had been flying for over 30 years and was nearly 7.5 billion miles away, used its 28 volt power unit to successfully transmit data to Earth.

Surely this is one of the greatest scientific and technological achievements ever?

Pioneer 10/11

I'll just repeat that. Nearly 7.5 billion miles away. And the data was received. But now, if I walk just a few streets to the south of here, then my smartphone reception disappears and I can no longer receive or transmit information.

From the now-archived NASA page on Pioneer 10 (November 5th 2004):

Launched on 2 March 1972, Pioneer 10 was the first spacecraft to travel through the Asteroid belt, and the first spacecraft to make direct observations and obtain close-up images of Jupiter. Famed as the most remote object ever made by man through most of its mission, Pioneer 10 is now 8 billion miles away.

Pioneer 10 made its closest encounter to Jupiter some thirty years ago on 3 December 1973, passing within 81,000 miles of the cloudtops. This historic event marked humans' first approach to Jupiter and opened the way for exploration of the outer solar system - for Voyager to tour the outer planets, for Ulysses to break out of the ecliptic, for Galileo to investigate Jupiter and its satellites, and for Cassini to go to Saturn and probe Titan. During its Jupiter encounter, Pioneer 10 imaged the planet and its moons, and took measurements of Jupiter's magnetosphere, radiation belts, magnetic field, atmosphere, and interior. These measurements of the intense radiation environment near Jupiter were crucial in designing the Voyager and Galileo spacecraft.


Pioneer 10 made valuable scientific investigations in the outer regions of our solar system until the end of its science mission on 31 March 1997. The Pioneer 10 weak signal continued to be tracked by the DSN as part of an advanced concept study of communication technology in support of NASA's future interstellar probe mission. The power source on Pioneer 10 finally degraded to the point where the signal to Earth dropped below the threshold for detection in its latest contact attempt on 7 February, 2003. Pioneer 10 will continue to coast silently as a ghost ship through deep space into interstellar space, heading generally for the red star Aldebaran, which forms the eye of Taurus (The Bull). Aldebaran is about 68 light years away and it will take Pioneer over 2 million years to reach it.

In a few months time, Pioneer 10 will be 10 billion miles away from Earth. Here's the plaque, designed by Carl Sagan, that it carries for any curious alien races to decipher (and hopefully they won't do this):


It is good to remember that the most amazing, challenging things mankind has done in space aren't always the most visible, such as Space Shuttles roaring off launchpads. Often, it's the stuff that happens far beyond eyesight, or outside of the visible spectrum. Here's Isaac Asimov talking a bit about Pioneer 10:

The physics department at the University of Iowa did much of the monitoring of Pioneer 10 (and other spacecraft). Their page, Termination of Pioneer 10's Mission concludes with:
Pioneer 10 called home for over thirty years of spaceflight. Its future is now transferred from NASA to Isaac Newton and Johannes Kepler, neither of whom could be reached for comment.

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